/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jackrabbit.webdav.security.report;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import javax.servlet.http.HttpServletResponse;

import org.apache.jackrabbit.webdav.DavConstants;
import org.apache.jackrabbit.webdav.DavException;
import org.apache.jackrabbit.webdav.DavResource;
import org.apache.jackrabbit.webdav.DavServletResponse;
import org.apache.jackrabbit.webdav.property.DavPropertyName;
import org.apache.jackrabbit.webdav.property.DavPropertyNameSet;
import org.apache.jackrabbit.webdav.security.SecurityConstants;
import org.apache.jackrabbit.webdav.version.report.Report;
import org.apache.jackrabbit.webdav.version.report.ReportInfo;
import org.apache.jackrabbit.webdav.version.report.ReportType;
import org.apache.jackrabbit.webdav.xml.DomUtil;
import org.apache.jackrabbit.webdav.xml.Namespace;
import org.apache.jackrabbit.webdav.xml.XmlSerializable;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

/**
 * <code>SearchablePropertyReport</code> identifies those properties that may be
 * searched using the {@link PrincipalSearchReport DAV:principal-property-search
 * REPORT}. This report must be supported on all collections identified in the
 * value of a DAV:principal-collection-set property.
 * <p/>
 * The request body MUST be an empty DAV:principal-search-property-set element.
 * <p/>
 * The response body MUSt be a DAV:principal-search-property-set XML element
 * with the following structure:
 * 
 * <pre>
 *  &lt;!ELEMENT principal-search-property-set (principal-search-property*) &gt;
 *  &lt;!ELEMENT principal-search-property (prop, description) &gt;
 *  prop: see RFC 2518, Section 12.11
 *  &lt;!ELEMENT description #PCDATA &gt;
 *  Human readable description. Note, that the language of the description must
 *  be indicated by the xml:lang attribute.
 * </pre>
 * 
 * Note that a DAV:principal-search-property XML element is requiered for each
 * property that may be searched with the DAV:principal-property-search REPORT.
 */
public class SearchablePropertyReport implements Report {

	// --------------------------------------------------------< inner class
	// >---
	/**
	 * Inner class encapsulating the DAV:principal-search-property
	 */
	private class PrincipalSearchProperty implements XmlSerializable {

		private static final String XML_PRINCIPAL_SEARCH_PROPERTY = "principal-search-property";
		private static final String XML_DESCRIPTION = "description";
		private static final String ATTR_LANG = "lang";

		private final DavPropertyName propName;
		private final String description;
		private final String language;
		private final int hashCode;

		private PrincipalSearchProperty(DavPropertyName propName,
				String description, String language) {
			if (propName == null) {
				throw new IllegalArgumentException(
						"null is not a valid DavPropertyName for the DAV:principal-search-property.");
			}
			this.propName = propName;
			this.description = description;
			this.language = language;
			hashCode = propName.hashCode();
		}

		@Override
		public boolean equals(Object obj) {
			if (obj == this) {
				return true;
			}
			if (obj instanceof PrincipalSearchProperty) {
				PrincipalSearchProperty other = (PrincipalSearchProperty) obj;
				// ignore the optional description/language
				return hashCode == other.hashCode;
			}
			return false;
		}

		@Override
		public int hashCode() {
			return hashCode;
		}

		/**
		 * @see XmlSerializable#toXml(Document)
		 */
		public Element toXml(Document document) {
			Element psElem = DomUtil.createElement(document,
					XML_PRINCIPAL_SEARCH_PROPERTY, SecurityConstants.NAMESPACE);
			// create property set from the single property name
			DavPropertyNameSet pnSet = new DavPropertyNameSet();
			pnSet.add(propName);
			psElem.appendChild(pnSet.toXml(document));
			// append description if present
			if (description != null) {
				Element desc = DomUtil.addChildElement(psElem, XML_DESCRIPTION,
						SecurityConstants.NAMESPACE, description);
				if (language != null) {
					DomUtil.setAttribute(desc, ATTR_LANG,
							Namespace.XML_NAMESPACE, language);
				}
			}
			return psElem;
		}
	}

	/**
	 * The report name
	 */
	public static final String REPORT_NAME = "principal-search-property-set";

	/**
	 * The report type
	 */
	public static final ReportType REPORT_TYPE = ReportType.register(
			REPORT_NAME, SecurityConstants.NAMESPACE,
			SearchablePropertyReport.class);

	/**
	 * Constant used for the DAV:principal-search-property-set response element.
	 */
	public static final String XML_PRINCIPAL_SEARCH_PROPERTY_SET = "principal-search-property-set";

	/**
	 * Set collecting the DAV:principal-search-property entries.
	 */
	public final Set<PrincipalSearchProperty> searchPropertySet = new HashSet<PrincipalSearchProperty>();

	// -----------------------------------------------------< implementation
	// >---
	/**
	 * Add a property name that should be listed in the
	 * DAV:principal-search-property-set.
	 * 
	 * @param propName
	 *            a property name that may be searched in the
	 *            {@link PrincipalSearchReport}.
	 * @param description
	 *            Human readable description of the searchable property.
	 * @param language
	 *            defines in which language the description is written.
	 * @throws IllegalArgumentException
	 *             if propName is <code>null</code>.
	 */
	public void addPrincipalSearchProperty(DavPropertyName propName,
			String description, String language) {
		searchPropertySet.add(new PrincipalSearchProperty(propName,
				description, language));
	}

	/**
	 * @see Report#getType()
	 */
	public ReportType getType() {
		return REPORT_TYPE;
	}

	/**
	 * @see Report#init(DavResource, ReportInfo)
	 */
	public void init(DavResource resource, ReportInfo info) throws DavException {
		if (resource == null || info == null) {
			throw new DavException(HttpServletResponse.SC_BAD_REQUEST,
					"Unable to run report: WebDAV Resource and ReportInfo must not be null.");
		}
		if (!getType().isRequestedReportType(info)) {
			throw new DavException(HttpServletResponse.SC_BAD_REQUEST,
					"Expected report type: '" + getType().getReportName()
							+ "', found: '" + info.getReportName() + ";" + "'.");
		}
		if (info.getDepth() > DavConstants.DEPTH_0) {
			throw new DavException(HttpServletResponse.SC_BAD_REQUEST,
					"Invalid Depth header: " + info.getDepth());
		}
	}

	/**
	 * @return false Status code of after a successful completion must be
	 *         {@link DavServletResponse#SC_OK 200 (ok)}.
	 * @see Report#isMultiStatusReport()
	 */
	public boolean isMultiStatusReport() {
		return false;
	}

	/**
	 * @see Report#toXml(Document)
	 */
	public Element toXml(Document document) {
		Element rootElem = DomUtil.createElement(document,
				XML_PRINCIPAL_SEARCH_PROPERTY_SET, SecurityConstants.NAMESPACE);
		Iterator<PrincipalSearchProperty> it = searchPropertySet.iterator();
		while (it.hasNext()) {
			PrincipalSearchProperty psp = it.next();
			rootElem.appendChild(psp.toXml(document));
		}
		return rootElem;
	}
}